[racket-dev] Typed versions of untyped collections

I don't understand Matthias's performance comments. If, in TR (require
plot) actually gives me a typed version of the library and in R (require
plot) gives me the untyped version of the library, then I am avoiding the
performance the untyped/typed performance overhead properly. If, on the
other hand, if I have to commit that (require plot) gives me either the
untyped or the typed version, then I have to suffer the performance
overhead when I require it from the "wrong" context.

Neil's original complaint also has validity, I think: if he provides a
plot/typed today, and then later ports plot so it is typed, then he has to
keep this extra thing around for what appears to not be a very good reason.

And while I do understand Sam's reluctance to mess with module resolution,
I think that just not solving this problem is worse.

And finally (and perhaps this is the root of the problem), I cannot
understand what TR actually does by reading its documentation.

For example, the docs for 'require' do not explain why I can make a copy of
"list.rkt" (in the racket collection), call the copy "listt.rkt" and have
that copy not work, but the original one does. Clearly TR is not just
"get[ting] *exactly* the same file as in R", so I think Sam's comments are
off base.

Robby

On Mon, Dec 17, 2012 at 2:51 PM, Sam Tobin-Hochstadt <samth at ccs.neu.edu>
wrote:
>
> On Mon, Dec 17, 2012 at 3:27 PM, Robby Findler
> <robby at eecs.northwestern.edu> wrote:
> > I've long thought something along these lines is a good idea, but
perhaps
> > what I think is a good idea isn't what Matthias and Sam think is the bad
> > idea.
> >
> > I think that it makes sense for 'require' in typed-racket to look in a
> > different place than 'require' in untyped racket looks so that one can
write
> > the same require spec (in both the docs and the code) and have two
versions
> > of the same library, one that is typed and one that isn't typed. Then,
then
> > library writer, if they choose, can decide who pays what for going (or
not)
> > across the boundary between typed and untyped. (Or maybe submodules
would be
> > better.)
>
> I think this is exactly what Eli was suggesting, and what I think is a
bad idea.
>
> > I think this is already happening in TR anyways, when I write
> >
> >   (require racket/list)
> >
> > I don't get the same file being loaded when that is in a TR program as
when
> > it is in a R program.
>
> You get *exactly* the same file as in R.  I think that (a) this is a
> valuable invariant and (b) the mechanisms for violating this invariant
> are all very worrying.
>
> Sam
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